MROP - Clarke

Question 1

Conceptus versus Fetus

Answer 1

Conceptus = embryo or fetus w/ all its membranes & accessory structures

Fetus = embryo that has completed organogenesis - recognizable as a memeber of its species

Question 2

What are the 4 requirements for establishment of pregnancy?

Answer 2

1. Fertilization
2. Early embryonic development
3. MROP
4. Placentation

Question 3

In early days of pregnancy in the cow & ewe, the embryo is __?__ to the CL

Answer 3

ipsilateral

Question 4

In the mare, the embryo’s position in the uterus up until day 16 is what?

Answer 4

Shifting between horns with no relationship to the CL.

Question 5

MROP has negative feedback on what hormone?

Answer 5

Prostaglandin (PGEF2alpha) – this hormone will luteolyse the CL if no MROP!!

Question 6

When does MROP occur in the cow? What is the signal?

Answer 6

Day 15-18 (from ovulation).
- signal = bovine interferon tau (INF-𝜏)
- recall: estrus in cow = 24h -> ovulation -> diestrus = 14d.

Question 7

Gestation Length:
1. Cow
2. Mare
3. Ewe
4. Sow
5. Bitch
6. Queen

Answer 7

1. Cow = b/w 9-10mo
2. Mare = b/w 11-12mo
3. Ewe = 5mo
4. Sow = 3mo, 3wk, 3d
5. Bitch = 65d
6. Queen = 2mo

Question 8

P4
- origins during pregnancy
- functions

Answer 8

1. Ovaries (from CL luteal cells - early)
2. Placenta (mid to late)

Functions: myometrial gland prolif., uterine quiescence (myometrial inhib.), mammary development

Question 9

What is the pattern of estrogens during pregnancy?

Answer 9

Gradual increase w/ peak around time of parturition
- primer for oxytocin (myometrial receptors), P4 & prolactin (both for mammary development)

Question 10

In what species does the placenta (luteal-independent) take over during gestation?

relies on placenta for progesterone

Answer 10

• cow
• ewe
• mare

Question 11

In what species is the CL (luteal-dependent) functioning throughout gestation?

relies on CL for progesterone over the placenta

Answer 11

• doe
• sow
• bitch
• queen